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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-01-27 10:50:19 +0100
committerAlex Shi <alex.shi@linaro.org>2016-11-14 14:40:16 +0800
commita916d13d03d627145048c944130cc595b4642282 (patch)
tree2f02f1dd93626d54a6375bd561d82ae5be657d1e
parent762f201f0a4445cec9cd8130dde538d946aedee1 (diff)
downloadlinux-linaro-stable-a916d13d03d627145048c944130cc595b4642282.tar.gz
arm64: allow vmalloc regions to be set with set_memory_*
The range of set_memory_* is currently restricted to the module address range because of difficulties in breaking down larger block sizes. vmalloc maps PAGE_SIZE pages so it is safe to use as well. Update the function ranges and add a comment explaining why the range is restricted the way it is. Suggested-by: Laura Abbott <labbott@fedoraproject.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> (cherry picked from commit 95f5c80050ad723163aa80dc8bffd48ef4afc6d5) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--arch/arm64/mm/pageattr.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index cf6240741134..0795c3a36d8f 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -14,6 +14,7 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sched.h>
+#include <linux/vmalloc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
@@ -44,6 +45,7 @@ static int change_memory_common(unsigned long addr, int numpages,
unsigned long end = start + size;
int ret;
struct page_change_data data;
+ struct vm_struct *area;
if (!PAGE_ALIGNED(addr)) {
start &= PAGE_MASK;
@@ -51,10 +53,23 @@ static int change_memory_common(unsigned long addr, int numpages,
WARN_ON_ONCE(1);
}
- if (start < MODULES_VADDR || start >= MODULES_END)
- return -EINVAL;
-
- if (end < MODULES_VADDR || end >= MODULES_END)
+ /*
+ * Kernel VA mappings are always live, and splitting live section
+ * mappings into page mappings may cause TLB conflicts. This means
+ * we have to ensure that changing the permission bits of the range
+ * we are operating on does not result in such splitting.
+ *
+ * Let's restrict ourselves to mappings created by vmalloc (or vmap).
+ * Those are guaranteed to consist entirely of page mappings, and
+ * splitting is never needed.
+ *
+ * So check whether the [addr, addr + size) interval is entirely
+ * covered by precisely one VM area that has the VM_ALLOC flag set.
+ */
+ area = find_vm_area((void *)addr);
+ if (!area ||
+ end > (unsigned long)area->addr + area->size ||
+ !(area->flags & VM_ALLOC))
return -EINVAL;
if (!numpages)